1-methylamino-2-nitro-4-(2{40 -hydroxyethyl)-methylaminobenzene for dyeing human hair

ABSTRACT

An improved dye compound 1-methylamino-2-nitro-4-(2&#39;&#39;hydroxyethyl)-methylaminobenzene and a method of making it. A hair dye composition containing this compound and the method of dyeing hair with this composition.

United States Patent Inventors Gregoire Kalopissis Paris; Andree Bugaut,Boulogne sur Seine, both of France Appl. No. 508,578 Filed Nov. 18, 1965Patented Jan. 4, 1972 Assignee Societe anonyme dite: LOreal PriorityNov. 19, 1964 Luxembourg 47,385

1-METHYLAMINO-2-NITRO-4-(2'- HYDROXYETHYL)-METHYLAMINOBENZENE [56]References Cited UNITED STATES PATENTS 2,687,431 8/1954 Marschall260/573 X 2,750,326 6/l956 Eckardt..... l67/88 2,750,327 6/ l 956Eckardt l67/88 3,168,442 2/ l 965 Brunner et al l67/88 FOREIGN PATENTS13,956 4/ l 905 Great Britain 260/573 OTHER REFERENCES Wagner et 20.,Synthetic Organic Chemistry, John Wiley & Sons, Inc., New York, (l953),pp. 572, 666- 667, 678 and 679.

Noller, Chemistry of Organic Compounds, 2nd Ed., W. B. Saunders Co.,Philadelphia, Pa. l957), pp. 478- 479.

Primary Examiner-Albert T. Meyers Assistant Examiner-Vera C. ClarkeAttorneyHolcombe, Wetherill & Brisebois ABSTRACT: An improved dyecompound l-methylamino-Z- nitro'-4-(2'-hydroxyethyl)-methylaminobenzeneand a method of making it. A hair dye composition containing thiscompound and the method of dyeing hair with this composition.

l-METHYLAMINO-2-NlTRO-4-(2 '-HYDROXYETHYL)- METHYLAMINOBENZENE FORDYEING HUMAN HAIR Nitroparaphenylenediamine is a known active ingredientused in dyes for living hair.

Various substituted products have been proposed in order to producedeeper shades than those produced by nitroparaphenylenediamine itself,and among these are alkyl groups and hydroalkyl groups.

In particular the use of trihydroxyalkylated derivatives ofnitroparaphenylenediamine has been suggested, and especially thosetrihydroxyethyls having a hydroxyethyl radical on the amino group in theortho position of the nitro group and two hydroxyethyl radicals on theamino group in the meta position of the nitro group.

However, it is very difiicult to obtain without tedious purification acommercially satisfactory yield of a trihydroxyethylated derivative ofthe type in question from nitroparaphenylenediamine, for example, byhalohydrin action, for the substitution of the hydroxyethylated groupsfor the hydrogens of the amine functions leads in practice not to a puretrihydroxyethylated product, but instead to a mixture of mono-, di-, ortrisubstituted products, each having a dyeing power of its own, saidmixture often comprising also tarry impurities.

Under the operating conditions which prevail during this substitution,the proportions within the resulting mixture vary, and the shadesproduced when the mixture is used cannot therefore be exactlyreproduced.

The object of the present invention is to provide a new nitrated hairdye and the coloring compositions which can be made with this new dye.

The new dye is 1-methylamino-2-nitro-4-(2-hydroxyethyl)-methylaminobenzene.

The invention also comprises a method of manufacturing this new dye.This process consists in starting with l-amino- 2-nitro-4-methylaminobenzene, transforming this by methylation intol-methylamino-2-nitro-4-methylaminobenzene, and subjecting the resultingproduct to hydroxyethylation, using a glycol halohydrin.

In this process the amine function in position 1 is methylated byblocking the position of the hydrogen atom carried by the amine group inposition 4with acetic anhydride, then blocking the position of one ofthe hydrogen atoms of the amine function in position 1 withparatoluene-sulfochloride, methylating the resulting product with aneutral methyl sulfate, and finally freeing the two previously blockedpositions using first sulfuric acid to detach the tosyl group carried bythe nitrogen atom in position 1, and then hydrochloric acid to detachthe acetyl group carried by the nitrogen atom in position 4.

Applicants have discovered that, under the foregoing conditions, thenitro group is readily hydroxyethylated in the meta position with acommercially satisfactory yield, and without impurities. In this way,since a methyl group on one of the amine groups may be easilysubstituted on the initial product, after which a hydroxyethyl group issubstituted on the other amino group, a product which will produceconstant, reproducible, results is obtained, since there is nocontamination by any secondary coloring agent.

It has been determined that with l-methylamino-2-nitro-4-(2'-hydroxyethyl)-methylaminobenzene perfectly uniform deep shades ofviolet are obtained. It should moreover be noted that this dye has anexcellent affinity for the keratinic fibers of human hair and that thehair dyes made with it are especially resistant to shampooing, yet haveno coloring effect on the scalp.

The hair dyes comprising the composition according to the invention aresimple aqueous solutions containing the composition, preferably havingan alkaline pH. No oxidizing agent is required to develop the color.Various additives known in the hair-coloring art may be included, suchas organic solvents, thickening agents, detergents, and lacquers.

The time during which the hair-coloring solutions should be kept incontact with the hair varies within broad limits, but is preferablybetween 5 and 30 minutes.

The temperature of application may also be varied, but in most cases thedye is applied at room temperature. The pH of these solutions is usuallybetween 7 and 10 and preferably between 8 and 9.5. Among the alkalineproducts which may be used to adjust the pH are ammonia, any organicbase, for example and alkylamine, an alkanolamine, or a heterocyclicamine. The concentration of the dye may be varied over a wide range, butthis concentration is preferably between 0.l and 3 percent.

It should be noted that the dye according to the invention may be mixedwith other dyes, whether nitrated, azo,

anthraquinone, or of any other type conventionally used for dyeing hair.

The process of preparing l-methylamino-2-nitro-4(2hydroxyethyl)-methylaminobenzene in accordance with the invention willnow be described, but it will be appreciated that not only bromohydrin,but any other halohydrin of ethanediol, can be used for thehydroxyethylation.

Preparation of 7-amino-2-nitro-4-methylacetaminobenzene.

0.258 moles of l-amino-2-nitro-4-methylaminobenzene (i.e. 43.2 g.) aredissolved in cm. of dioxane and 0.266 moles (25.2 cm) of aceticanhydride are added little by little, while maintaining the temperatureat 70 C. After cooling 44.9 g. of an acetylated derivative which meltsat 165 C. are obtained by drying.

Preparation of paratoluenel -sulfonylamino-2-nitro-4-methylacetaminobenzene.

0.43 moles (82 g.) of paratoluene-sulfochloride is added to a solutionof 0.287 moles (60 g.) of l-amino-2-nitro-4- methylacetaminobenzene at atemperature of 40 to 45 C., little by little, while stirring themixture. After the addition has been completed, the mixture is kept at45 C. for 2 hours, emptied into a liter of cold water, after which sodais added to yield the desired product in the form of sodium tosylate.Any of the starting composition which remains untransformed is extractedusing methyl isobutyl ketone. The aqueous phase is acidified withhydrochloric acid and, after cooling for several hours, 72 g. ofparatoluene-l-sulfonylamino-2-nitr0-4- methylacetaminobenzene is removedby drying. After recrystallization, this product melts at 120 C.

Analysis of the End Product Calculated Found C% 52.89 53.03-52.82 H%4.68 4.55-4.59 N96 N57 ll.53-ll.70

Preparation of methyl-paratoluene-1-sulfonylamino-2-nitro-4-methylacetaminobenzene.

Analysis of End Product Calculated Found C 54.1 1 54.08-54.04 me 5.045064.92 N% n14 11.35-11.30

Preparation of 1-methylamino-2-nitro-4- methylacetaminobenzene.

Analysis of End Product Calculated Found Preparation ofl-methylamino-2-nitro-4- methylaminobenzene.

0.05 moles (l 1.2 g.) of l-methylamino-2-nitro-4-methylacetaminobenzeneare heated to reflux in 26 cm. of concentrated hydrochloric acid in 26cm. of water. After cooling, the end product is obtained by drying inthe form of a hydrochlorate. The hydrochlorate is dissolved in water andammonia added to render the pH alkaline. Drying, after cooling, yields 8g. of 1-methy1amino-2-nitro-4- methylaminobenzene which melts at 1 14 C.

Analysis of End Product Calculated Found C% 53.00 52.67-52.52 H% 6.076.056.09 N% 23.21 23.32-23.36

Preparation of 1-methylamino-2-nitro-4-( 2 '-hydroxyethyl)-methylaminobenzene.

Analysis of End Product Calculated Found C% 53.33 53.21-53.24 H% 6.666.97-6.85 N% 18.66 18.90-48.66

Two examples will now be given, showing how the dyes according to theinvention may be used in a preparation for dyeing the hair.

EXAMPLE 1 The following solution is prepared:

l-methylamino-2-nitro-4-( 2'-hydroxy- I eIhyU-mcthylnminobcnezene l.g.oxyethylated lauric alcohol having 10.5

molecules of ethylene oxide 5 g.

ammonia q.s.p. pH 7 water q.s.p. 100 g.

This solution is applied to completely white hair for 10 minutes. Afterthe waiting period is over, the hair is rinsed, washed, and dried. Anintense mauve shade results.

EXAMPLE 2 1-methylamino-2-nitr0-4-(2'-hydroxy- This solution is appliedto completely white hair. It is left for 15 to 20 minutes, after whichthe hair is rinsed, shampooed, and dried. A clear copperish chestnutshade is obtained.

It will of course be appreciated that the processes of preparing the dyeand the methods of applying it which have just been described may bemodified as to detail without thereby departing from the basicprinciples of the invention.

What we claim is:

1. l-methylamino-2-nitro-4-( 2 -hydroxyethyl methylaminobenzene.

2. A composition for dyeing hair comprising an aqueous solutioncontaining hair-dyeing amounts of the compound of claim 1.

3. A hair-dyeing composition as claimed in claim pH between 7 and 10.

4. A hair-dyeing composition as claimed in claim 2 having a pH between 8and 9.5.

5. A hair-dyeing composition as claimed in claim 2 in which theconcentration of said compound lies between 0.1 and 3 percent.

6. The method of preparing 1-methylamino-2-nitro-4-(2'-hydroxyethyl)-methylaminobenzene comprising blocking the position of thehydrogen atom carried by the amine group in position 4 ofl-amino-2-nitro-4-methylaminobenzene by reacting it with aceticanhydride, and blocking the position occupied by one of the hydrogenatoms of the amine function in position 1 by reacting it withparatoluene-sulfochloride, methylating the resulting product with methylsulfate, freeing the two blocked positions by reacting the methylatedcompound first with sulfuric acid and then hydrochloric acid, thenreacting the resulting compound with glycol halohydrin tohydroxyethylate the nitrogen atom in position 4.

7. The method claimed in claim 6 in which the halohydrin is glycolbromohydrin.

8. The method of dyeing human hair which comprises the step of applyingthereto a composition containing dyeing amounts of1-methylamino-2-nitro-4-(2'-hydroxyethyl)- methylaminobenzene.

2 having a

2. A composition for dyeing hair comprising an aqueous solutioncontaining hair-dyeing amounts of the compound of claim
 1. 3. Ahair-dyeing composition as claimed in claim 2 having a pH between 7 and10.
 4. A hair-dyeing composition as claimed in claim 2 having a pHbetween 8 and 9.5.
 5. A hair-dyeing composition as claimed in claim 2 inwhich the concentration of said compound lies between 0.1 and 3 percent.6. The method of preparing1-methylamino-2-nitro-4-(2''-hydroxyethyl)-methylaminobenzene comprisingblocking the position of the hydrogen atom carried by the amine group inposition 4 of 1-amino-2-nitro-4-methylaminobenzene by reacting it withacetic anhydride, and blocking the position occupied by one of thehydrogen atoms of the amine function in position 1 by reacting it withparatoluene-sulfochloride, methylating the resulting product with methylsulfate, freeing the two blocked positions by reacting the methylatedcompound first with sulfuric acid and then hydrochloric acid, thenreacting the resulting compound with glycol halohydrin tohydroxyethylate the nitrogen atom in position
 4. 7. The method claimedin claim 6 in which the halohydrin is glycol bromohydrin.
 8. The methodof dyeing human hair which comprises the step of applying thereto acomposition containing dyeing amounts of1-methylamino-2-nitro-4-(2''-hydroxyethyl)-methylaminobenzene.